To provide lubricant oil with a certain new feature or improved existing features during the production of the lubricant oil, various additives such as an extreme pressure additive, a detergent, a dispersant, an antioxidant and a tackifier are usually added to the base oil of the lubricant oil. The detergent, among the numerous additives for lubricant oil, is widely used for various purposes and is present at a significant ratio among the additives for lubricant oil.
The detergent is a substance with a surface activity, which is capable of absorbing solid particle contaminants in the lubricant oil and enabling such contaminants to suspend at the surface of the lubricant oil, in order to ensure clear lubricant oil is used for lubricating cycles and to avoid the resulting high temperature and paint film, thereby enabling any insoluble substance such as jellies and carbon deposition resulting from the oxidation of the lubricant oil to be suspended in the lubricant oil at a colloidal state without being deposited on any parts of an engine, or enabling the lubricant oil to clean off the jellies and carbon deposition deposited on the parts of the engine through its cleaning effect. The detergent of the substance described above is also referred to as a detergence dispersant because the dispersant role of the substance.
For example, the presently available detergents for lubricant oil comprise a synthetic calcium alkyl benzene sulfonate having a low base value, a linear synthetic calcium alkyl benzene sulfonate having a high base value, a long-chain linear alkyl benzene synthetic calcium sulfonate having a high base value, a synthetic calcium dialkyl benzene sulphonate having a high base value, a long-chain linear alkyl benzene synthetic magnesium sulfonate having a high base value, a sulfurized calcium alkyl phenolate having a high base value, polyisobutenyl succinimide, polyisobutenyl succinimide boride, polyisobutenyl succinimide having a high molecular weight, and polyisobutenyl succinimide boride having a high molecular weight.
In the prior art, it is known to adopt a compound of alkaline earth metal salt of organic carboxylic acid as the additive for the lubricant oil. The alkaline earth metal salt of organic carboxylic acid is characterized by its dispersancy which facilitates to keep the interior of the cylinder of the engine clean and eliminates the carbon deposition on the piston and piston grooves, thereby avoiding the piston ring sticking. Therefore, the alkaline earth metal salt of organic carboxylic acid can be used as the detergent (or the detergence dispersant) for lubricant oil.
The process for preparing the alkaline earth metal salt or overbased alkaline earth metal salt of organic acid is also known. Due to the alkalinity reserve provided by the overbasing, when used as a composition of the lubricant oil, the alkaline earth metal salt or overbased alkaline earth metal salt of organic acid can neutralize acidic compound generated during the operation of an engine. Therefore, any potential sludge is dispersed due to the dispersibility of the organic acidic alkaline earth metal salt, thereby accelerating the neutralization of acidic matters generated by the sludge.
A salicylic acid with high alkaline may be prepared by overbasing the corresponding alkyl salicylic acid or alkyl salicylate methyl ester. The alkyl group generally contains a long-chain alkyl with more than about 14 carbon atoms to achieve sufficient oil solubility. A traditional method for preparing the alkyl salicylic acid includes: alkylating a phenol to obtain an alkyl phenol; and carbonating the alkyl phenol by the Kolbe-Schmitt reaction to obtain the alkyl salicylic acid. Alternatively, the alkyl salicylic acid may be prepared by directly alkylating a salicylic acid or salicylate methyl ester with α-olefin using a catalyst such as a sulphuric acid, a methanesulfonic acid, and emathlite.
U.S. Pat. No. 1,998,750 A disclosed that a salicylic acid is condensed with any nonaromatic monohydric alcohol having from 5 to 7 carbon atoms, or with compounds capable of furnishing a pentyl group, a hexyl group, a cyclohexyl group, or a heptyl group at the presence of a Sulfuric Acid, to generate an alkyl salicylic acid.
U.S. Pat. No. 3,372,116 A discloses a method for preparing an alkaline salicylate, including reacting, at a temperature between about 25° C. and the reflux temperature, (A) a hydrocarbon-substituted phenol or a substantially neutral alkali metal salicylate or alkaline earth metal salicylate salt, (B) about 1-10 equivalents, per equivalent of (A), of a calcium or strontium base, and (C) carbon dioxide, in the presence of about 0.002-0.2 equivalent, per equivalent of calcium or strontium base, of a carboxylic acid having up to about 100 carbon atoms or an alkali metal, alkaline earth metal, to obtain the alkaline salicylate.
U.S. Pat. No. 4,810,398 A disclosed a process for the preparation of basic alkaline earth metal salts of a blend of organic carboxylic acid, which includes: (a) preparing a mixture of one equivalent of the blend of organic carboxylic acids and more than one equivalent amount of an alkaline earth metal hydroxide and/or oxide in a hydrocarbon solvent; (b) introducing carbon dioxide into the mixture obtained in an amount of at least 0.5 equivalent carbon dioxide per equivalent of excess alkaline earth metal; and (c) removing residual solids, if any, and an aqueous layer, if any. The blend of organic carboxylic acids comprise a C8-30 alkyl salicylic acid and one or more alkane carboxylic acids in which the alkyl moiety is branched and has from 4 to 40 carbon atoms. Such a salt has dispersant properties and is suitable for use in lubricating oil and fuel compositions.
U.S. Pat. No. 4,869,837 A disclosed a process for the preparation of a basic alkaline earth metal salts of a blend of organic carboxylic acids, including: (a) preparing a mixture of one equivalent of the blend of organic carboxylic acids and more than one equivalent of an alkaline earth metal hydroxide and/or oxide in a hydrocarbon solvent; (b) introducing carbon dioxide into the mixture obtained in an amount of at least 0.5 equivalent carbon dioxide per equivalent of excess alkaline earth metal; and (c) removing residual solids, if any, and an aqueous layer, if any, whereby. The blend of organic carboxylic acids comprises an oil-soluble alkyl salicylic acid and one or more hydrocarbon substituted succinic acids or anhydrides, in which the hydrocarbon radical has a number average molecular weight from 120 to 5000.
U.S. Pat. No. 4,876,020 A disclosed a lubricating oil formula, including a lubricating base oil, one or more overbased alkaline earth metal salts of an aromatic carboxylic acid, and a stabilizing agent which has been selected from a polyalkoxylated alcohol having a molecular weight from 150 to 1500.
U.S. Pat. No. 5,049,685 A disclosed a substituted salicylic acids and salts thereof that have good solubility in water, organic solvent or organic polymeric. The substituted salicylic acids and salts thereof are very favorable as bactericidal germicidal agents, stabilizers for polymeric compounds or color developing agents for recording materials.
U.S. Pat. No. 5,415,792 A disclosed overbased alkyl salicylate which are useful additives for lubricant oil compositions. The overbased alkyl salicylate compositions impart detergency and disperancy to the lubricant oil composition as well as provide for alkalinity reserve.
U.S. Pat. No. 5,434,293 A disclosed is a method for alkylating alkyl salicylate using a solid acidic alkylation catalyst and approximately equimolar amounts of alkyl salicylate and alkylating feedstock.
U.S. Pat. No. 5,451,331 A disclosed a process for the production of a lubricating oil additive having a TBN greater than 300. The process includes reacting, at elevated temperature, an alkyl salicylic acid, alkaline earth metal base, a lubricating oil, a carbon dioxide, and an alcohol. The process necessarily utilize inorganic halide or ammonium alkanoate.
U.S. Pat. No. 5,458,790 A disclosed an additive concentrate having a TBN greater than 300 for incorporation into a finished lubricating oil. The additive concentrate comprises a lubricant oil and a lubricating oil soluble overbased alkaline earth metal hydrocarbyl salicylate modified by reaction, which mainly includes: (a) an aldehyde, and (b) from 2 to 40% by weight, based on the weight of the concentrate, of either (i) a carboxylic acid, or (ii) a di- or poly-carboxylic acid containing from 36 to 100 carbon atoms or an acid anhydride, acid chloride or ester thereof.
U.S. Pat. No. 5,652,203 A disclosed a process for the preparation of a lubricating oil additive. In the process, an aromatic carboxylic ester is subjected to ring alkylation with an olefin, reacted with the oxide or hydroxide or an alcoholate of a divalent metal and carbon dioxide with the removal of formed water and/or an alcohol from the reaction mixture. The lubricating oil additive provides excellent oxidation stability, low susceptibility to carbonization and cleanability as compared with the conventional, commercially-available additives.
U.S. Pat. No. 5,734,078 A disclosed a process for the production of an alkyl salicylic acid, in which the alkyl substituent has at least 6 carbon atoms, comprising reacting salicylic acid with an olefin having at least 6 carbon atoms at elevated temperature in the presence of sulphuric acid as a catalyst. The alkyl salicylic acid is overbased at temperature from 50 to 100° C. in the presence of an organic solvent.
U.S. Pat. No. 5,792,735 disclosed a lubricating oil composition suitable for use in low or medium speed diesel engines, which comprises a fuel oil, a hydrocarbyl-substituted phenate, and at least one of a hydrocarbyl-substituted salicylate and a hydrocarbyl-substituted sulphonate. The hydrocarbyl-substituted phenate is preferably one modified by incorporation of a carboxylic acid of formula RCH(R1)CO2H, where R is C10-C24 alkyl group, and R1 is hydrogen or a C1-C4 alkyl group, e.g. stearic acid.
U.S. Pat. No. 6,034,039 A disclosed complex detergents that provide improved deposit control and corrosion protection in crankcase lubricants. The lubricating oil composition comprises a mixture of at least two metal-containing detergents, a first detergent (a), being a metal phenate, sulphonate, salicylate, naphthenate, or carboxylate, and a second, detergent (b), being a calcium overbased detergent comprising a surfactant system derived from at least two surfactants, at least one of which is a sulphurized or non-sulphurized phenol or a derivative thereof and the other, or at least one other, of which is a surfactant other than a phenol surfactant, the proportion, as measured, of the phenol in the surfactant system being at least 45 mass %, and the overbased detergent having a TBN: % surfactant ratio of at least 14, advantageously at least 15, especially at least 19.
U.S. Pat. No. 6,200,936 A disclosed a process for the preparation of salicylization arene and its overbased product, and its use as a lubricating oil additive.
U.S. Pat. No. 6,348,438 A disclosed that an overbased alkaline earth metal single-aromatic ring hydrocarbyl salicylate-carboxylate is produced by overbasing a mixture of a single-aromatic ring hydrocarbyl salicylate, at least one solvent, a metal hydroxide, and an alkyl polyhydric alcohol alkaline earth metal hydroxide, by contacting that mixture with carbon dioxide under overbasing reaction conditions. The alkyl group of the alkyl polyhydric alcohol has from one to five carbon atoms. The overbased metal single-aromatic ring hydrocarbyl salicylate is treated, before, during, or subsequent to overbasing, with a long-chain carboxylic acid to form a single-aromatic ring hydrocarbyl salicylate-carboxylate.
U.S. Pat. Nos. 6,596,038 A and 6,802,874 A disclosed linear compounds in the form of oligomers or polymers, containing unsubstituted or substituted phenol units and unsubstituted or substituted salicylic acid units, and a synthesis process of the compounds. These compounds are useful as additives for lubricants and fuels. Metal salts of these compounds are useful as lubricant additives.
U.S. Pat. No. 6,599,867 A disclosed overbased detergent additives for lubricating oils which comprise an organic substantially aromatic carboxylate, such as an alkyl salicylate, as a surfactant, and have a TBN of 200 or greater, an active ingredient content of 70 mass % or greater, a kinematic viscosity at 100 DEG C. of less than 1000 mm2s-1 and a basicity index (BI) of less than 13.
U.S. Pat. No. 7,009,072 A disclosed that the alkylation of a salicylic acid is conducted using C14 or greater linear alpha-olefins to produce oil soluble alkyl salicylic acids. The oil soluble alkyl salicylic acids are subsequently neutralized and overbased by carbonation of lime using CO2 in the presence of a promoter, such as methanol, and a surfactant, e.g., alkyl salicylic acid. The reaction mixture after overbasing is filtered and solvents are removed by distillation.
U.S. Pat. No. 7,045,654 A disclosed a process for the production of alkyl salicylic acids. The process comprises reacting a salicylic acid with an olefin having at least four carbon atoms at elevated temperature in the presence of a perfluoroalkylsulfonic acid, an alkylsulfonic acid, or an acidic clay as a catalyst.
U.S. Pat. No. 7,087,557 A disclosed a Styrenated salicylate, which has an anti-oxidant property, for use as a metal based detergent additive. In the presence of methanol as a promoter, the Styrenated salicylate is neutralized and overbased to result in the overbased Styrenated calcium or magnesium salicylate.
U.S. Pat. No. 7,456,136A disclosed a linear compound and a metal salt or boron-containing metal salt thereof, which contains one or more carboxyl-containing phenol units or derivatives thereof and one or more on average at least C18 hydrocarbyl-substituted hydroxyaromatic units or derivatives thereof connected by one or more divalent bridging groups. A concentrate contains the linear compound or metal salt thereof and an organic diluent is further disclosed. In addition, a lubricating oil composition contains a minor amount of the linear compound or metal salt thereof and a major amount of a lubricating base oil is disclosed.
Although the above detergents for lubricant oil are disclosed in the prior art, inorganic halide or ammonium alkanoate is required during the preparation of such detergents, and a hydrocarbon solvent is necessary during the preparation, resulting a high residual carbon value.